Billy Wilder's 1950 drama "Sunset Boulevard" wasn't the first movie to hold a mirror up to Hollywood. But it was the first to show it warts'n'all.

Take a trip down Sunset Blvd as we reveal what happened during the making of a scabrous Hollywood classic...

* Co-writer Charles Brackett conceived the idea as an exuberant Hollywood comedy in which an ageing silent movie star overcomes adversity and makes a successful comeback. It would develop into a savage look at the Hollywood dream turned sour, and Brackett's final collaboration with co-writer and director Billy Wilder.

* Wilder was paranoid about Hollywood discovering his plans, so he created a fictitious working title, "A Can of Beans". In a bid to throw everyone off the scent, he also created fantastical plotlines for the weekly meetings Brackett attended with the suits at Paramount Studios.

* Mae West was Wilder's first choice to play faded silent movie star Norma Desmond. Despite being 55, West saw herself as being in the prime of life and recoiled at the idea of playing a has-been. Other one-time greats to reject the role were Mary Pickford (she really did believe she was still big) and Pola Negra.

* Gloria Swanson and Billy Wilder had worked together once before, on "Music in the Air" (Swanson played the female lead in the 1934 musical, which Wilder co-wrote), but it was another director, George Cukor, who suggested her for the role. Swanson was living in New York and working in TV at the time, and took umbrage at Wilder's suggestion that she test for the part ("I was revolted. Never made a test in my life," she later recalled). It was only a "sweet-talking" intervention from George Cukor that changed her mind.

* Reporter and film critic DM Marshman Jr was a bridge partner of Wilder's. He became co-writer on the script after suggesting the idea of a relationship between Norma Desmond and a desperate young writer (Joe Gillis).

* Montgomery Clift was set to play the part of Joe Gillis, but dropped out two weeks before shooting was due to start, April 1949. Although Clift's agent said his client felt unable to give a convincing performance as a gigolo dating a woman twice his age, the truth was far more interesting: Clift was having an affair with singer Libby Holman, 30 years his senior. In his book "Billy Wilder on Hollywood", Maurice Zolotow alleges that the alcoholic Holman threatened to kill herself if Clift took the part.

* Having been turned down by his "Double Indemnity" star Fred MacMurray, Wilder next turned to William Holden, who was contracted to Paramount. The actor was pushed into the role by the studio, despite having misgivings about playing second-fiddle to Swanson. He went on to receive an Oscar nomination for his performance.

* The house used for Norma Desmond's decaying mansion wasn't actually situated on Sunset Blvd but Wilshire Blvd. Paramount rented it from its owner, J Paul Getty, with one condition: they could build a swimming pool in the grounds, but if Getty's wife didn't like the end result, they'd have to return the grounds to their original shrubbery-filled form. The house was demolished in 1957, and a 22-storey office block built in its place.

* Erich von Stroheim, who plays Norma Desmond's devoted servant Max, actually directed Swanson in the troubled 1929 silent movie "Queen Kelly". Swanson had von Stroheim fired from the movie after he'd racked up four hours of film and was only a third through. He part held the rights to the film, though, and refused to sanction its theatrical release. The first glimpse American viewers got of the 20-year-old movie was when Norma Desmond watches it on her home cinema during "Sunset Boulevard".

* The "waxworks" who play bridge with Norma Desmond are all real-life silent screen stars: comic genius Buster Keaton, Swedish starlet Anna Q Nilsson, and HB Warner - best known for biblical epic "The King of Kings" and as Mr Gower in "It's a Wonderful Life".

* Wilder's original opening and closing scenes were set in the Los Angeles County Morgue. They were cut after a disastrous test screening in which the audience collapsed with laughter at the sight of talking corpses (the planned intro). Wilder was present at the screening and asked a woman what she thought of the movie. "I never saw such a pile of s*** in all my life," was her blunt reply.

* After being delayed for six months, "Sunset Boulevard" finally opened in the US in the summer of 1950. At a gala screening on the Paramount lot, MGM mogul Louis B Mayer voiced the disgust of many Tinseltown insiders: "You bastard!" he shouted at Wilder. "You have disgraced the industry that made you and fed you. You should be tarred and feathered and run out of Hollywood." Wilder's response embodied the message of his movie: "F*** you!"